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Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/4/2002 Publication Date: N/A Citation: N/A Interpretive Summary: Subterranean termite damage and control efforts cost Americans an estimated 2 billion dollars annually. Although insecticides are the primary method of controlling subterranean termites, the bioassay methods used currently are crude and do not account for exchange of insecticide among nestmates by regurgitative feeding. Therefore, scientists at the Center for Medical, Agricultural and Veterinary Entomology and Formosan Subterranean Termite Research Laboratory have developed a novel bioassay technique capable of providing an accurate assessment of insecticide toxicity against the Formosan subterranean termite and other subterranean termite species. Furthermore, these scientists demonstrated that insecticide toxicity is higher when termites are held in a group as opposed to being held individually after insecticide treatment. This research provides a necessary method of evaluating insecticide efficacy in termites. Technical Abstract: Coptotermes formosanus workers were treated topically with insecticide and subsequently held in groups or individually to examine trophallactic and grooming behavioral effects on insecticide toxicity. Chlorpyrifos, cypermethrin, and chlordane toxicity was 1.4-, 1.5-, and 1.3-fold greater among workers held in groups compared with those held individually after insecticide treatment, respectively. Experiments were conducted to examin whether trophallaxis, cannibalism, or insecticide residue exposure contributed to the enhanced toxicity observed among termites held in groups after topical insecticide treatment. When workers were treated topically with chlordane and placed immediately with untreated workers, significantly greater numbers of untreated workers were killed compared with controls at all ratios (insecticide-treated:untreated). These data indicated that workers treated topically with insecticide were capable of somehow transferring a lethal dose of insecticide to untreated workers confined in the vial. Indeed, -chlordane was recovered from untreated workers which had been confined with chlordane#treated workers; significantly higher quantities of -chlordane were recovered from dead workers exposed to chlordane-treated workers compared with surviving workers exposed to chlordane-treated workers. |
